This invention relates to a method and apparatus for the reconditioning of conveyor belts, and in particular, to the method and apparatus by which the top worn portion of a conveyor belt may be stripped off to expose the surface underneath for reconditioning. This surface subsequently receives a layer of new material to recondition or restore the belt to its original dimensions and capabilities.
In various uses, such as quarry operations, steel mills and other heavy industrial uses, the conveyor belt has become a necessary and integral part of the manufacturing process. Because of the sometimes severe wear encountered by these conveyor belts in these and other industries it becomes necessary to replace or repair the belts at frequent intervals of time. In the industries of heaviest wear, as mentioned above, the cost of these conveyor belts and their replacements can add considerably to the cost of the end product or service, since they must be of extremely heavy and durable construction to withstand the adverse conditions such as weight and abrasion to which they are subjected.
This wear can occur in any of several different manners: longitudinal tearing, transverse tearing, or just normal wear. The physical abuses encountered while in service can, at times, wear the belt down to the underlying structural cables. At this point it becomes necessary to either purchase a new belt at a substantial expense or attempt to recondition the old one. The industry has generally elected to recondition old belts in view of the expense of new belts which cost up to $100.00 per linear foot. This high cost makes any process of reconditioning even if inefficient or crude attractive.
In general, when viewed in cross section, a conveyor belt consists of two portions, a bottom or lower portion which provides the structural strength and is generally composed of woven or twisted wire of roughly 1/4 inch diameter running the length of the belt in the direction parallel with the direction of travel of the belt. The wires are spaced approximately 1/4 inch apart from one another and completely encased in a belt material of rubber or other suitable flexible material. The top or load carrying portion consists of a relatively thick rubber or other material overlying and integral with that surrounding the wire structure. As already mentioned, this top or load carrying portion of the belt may become damaged or heavily worn, especially in the central area where the major amount of use takes place. Thus, a belt might develop an undesirable "belly", or cuts that cause the belt to weaken and even split laterally.
Prior to the subject invention and as taught by the prior art, repair was attempted by the slavish task of hand slitting and removing the top layer of the belt from the bottom structural portion. This hand process consisted of slitting strips 4 inches wide, the full length of the belt. The 4-inch strips were then forcibly ripped, again, by hand, from the lower structural portion to expose the surface underneath. This time consuming, labor-intensive process had to be done to the entire surface of the belt, requiring much time, strength and endurance by the laborers. After exposing a completely new surface on the belt, a new mat of rubber or other suitably strong, yet flexible surface is placed on the new surface of the belt and secured either with an adhesive or a combination of an adhesive and a vulcanizing process so that the entire top surface of the conveyor belt is replaced and once again ready for service. This manner of reconditioning of belts has not been found entirely satisfactory, both in terms of the time consumed and the results obtained. Contrary to most fields of endeavor, manual labor here produces a decidedly imperfect piece of work, resulting in a stripped portion having a structural bottom of varying thicknesses and imperfections.